Title

RHEL 9 SSH daemon must not allow rhosts authentication. (Cat II impact)

Discussion

SSH trust relationships mean a compromise on one host can allow an attacker to move trivially to other hosts.

Check Content

Verify the SSH daemon does not allow rhosts authentication with the following command: $ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*ignorerhosts' IgnoreRhosts yes If the value is returned as "no", the returned line is commented out, or no output is returned, this is a finding.

Fix Text

Configure the SSH daemon to not allow rhosts authentication. Add the following line in "/etc/ssh/sshd_config", or uncomment the line and set the value to "yes": IgnoreRhosts yes The SSH service must be restarted for changes to take effect: $ sudo systemctl restart sshd.service

Additional Identifiers

Rule ID: SV-258005r952206_rule

Vulnerability ID: V-258005

Group Title: SRG-OS-000480-GPOS-00227

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.